1. Field of the Invention
The present invention relates to an injection compression molding apparatus, an injection compression molding die, and an injection compression molding method wherein melted resin is injected, into a cavity that is formed by a stationary die and a movable die, from a nozzle attached to an injection apparatus and, then, the volume of the cavity is reduced, to compress the melted resin in the cavity, by moving the movable die toward the stationary die.
In the present invention, the injection compression molding includes both a so-called injection compression molding that moves the movable die in the die opening direction by injecting the melted resin into the cavity and then moves the movable die in the die closing direction again to compress the melted resin in the cavity, and a so-called injection press molding that injects the melted resin into the cavity while the movable die is stopped at a predetermined open position in advance and then moves the movable die in the die closing direction.
2. Description of the Related Art
Conventionally, an injection compression molding apparatus such as that described in patent document 1 is well-known. According to the description in the above publication, a nozzle abuts on a resin injection hole provided on a lower die that is a stationary die, and melted resin is injected from the nozzle into a cavity through a resin path, a resin reservoir and the like. Then, after the melted resin is injected into the cavity, in order to complete the molding process, an upper die that is a movable die is moved toward the lower die so that the melted resin in the cavity is compressed and the resin in the path is solidified for gate cutting.
[Patent Document 1]
    Japanese Examined Patent Publication (Kokoku) Hei 7-96238 (pp. 2–7)
However, in the injection compression apparatus described above, as the resin path, the reservoir and the like are formed between the resin injection hole provided on the bottom surface of the lower die and the cavity, there are problems in that:    (1) the construction of the dies is complicated and it is costly to manufacture the dies;    (2) since the resin is solidified in said path, reservoir and the like at the time of molding, loss of the resin as well as heat loss may occur in every molding process, which will result in poor energy efficiency;    (3) a device for taking out the resin that is solidified in the path, reservoir and the like at the time of molding is needed, or a device for cutting off the molded products from the resin that is solidified in the path, reservoir and the like is needed; and    (4) the melted resin that passes through a complicated pathway to reach the cavity may suffer pressure loss.